SUSTAINABLE LAND USE AND AMELIORATION OF SALT AFFECTED SOILS Lajos Blaskó Debrecen University Agricultural Centre Karcag Research Institute

The practice of reclamation of SAS in Hungary is two centuries old: the first guide on this topic : SÁMUEL TESSEDIK (1804): Über die Kultur und Benützung der so genannten Székes- Felder(≈”Salt affected soils”) in der Gegend an der Theiß. Lübeck, I.R. Patriotisches Wochenblatt f. Ungarn. revaluation of the achievements from viewpoint of sustainability

Community Society Environment Sustainable agriculture integrates three main goals:--environmental health, economic profitability, social and economic equity. For meeting the demands of ecological and economical points of sustainability the amelioration of soils must be revaluated first of all because of the changing climatic and economical situation. Economy sustainability of ameliorationSustainable agriculture

According the soil survey (SZABOLCS 1971, VÁRALLYAY 1992), the salt affected soil cover in Hungary about 1 million ha. (about 10% of total area) Karcag What to do with SAS? Trans Tisza Region

Goals : For an established land use decision - among others - the following questions must be answered: ▪What is the main trend of natural soil forming processes? What are the most effective means of soil improvement? It is a fundamental question if a negative (decreasing) salt balance is without subsurface drainage attainable or not What is the degree of the soil quality changes for shorter and longer term after amelioration? What are the most suitable cultivated crops of improved SAS

Material and methods The paper is based on the research results achieved by the following facilities: Karcag lysimeter experiment: salt balance monitoring Soil Information Monitoring System (TIM). Karcag-puszta long term experiment

Summarized results of salinization monitoring: According to the open air monitoring - in line with lysimeter results - in case of rain fed agriculture in the last two decades the increasing salt content was not characteristic, not even on the territories where earlier salt accumulation problems happened. It means, that the natural sinking of ground-water level is favorable from viewpoint of sustainability of amelioration.

More detailed results of Karcag-puszta experimental field: In 1977 the Research Institute of Debrecen Agricultural Univ. established complex amelioration stations on the main soil types of the Hungarian Plain, among them the Karcag-puszta experimental field represents the facility on salt affected soil. This site were chosen because it typified much of the salt affected soils of the Eastern part of the Hungarian Plain. This great spatial variety rises special methodological problems in case of plot experiments Theoretically the disadvantages effect of heterogenety could be moderated by the increase of the number of the replication, but this method is practically not applicable in the case of soil reclamation or amelioration experiments with drainage due to the limited capacities

Sampling: To determine the change of the soil properties[1] samples were taken from 112 surveyed points of 16 plots in 1977, 1981, and2000. The soil was sampled to the depth of 110 cm by each 10 cm deep layer. Beyond the sampling points 224 elevation reference points were also surveyed, hence the „z” co- ordinates provide the possibility of 3-D modelling (DTM[1] [1] The examined soil properties: pH (H 2 O), pH (KCl), Y 1, CaCO 3, Na 2 CO 3, K A, exchangeable Ca-, Mg-, K-, and Na, salt (%).[1]

Contour map of the experimental area The altitude difference between the higher and lower point of experimental field is 0.9 m m above Baltic sea level

Micro relief The micro-relief of salt affected soil forms basins and valleys with different run-off characteristics.

Run-off/run-on situations (SURFER 7.0) In the areas with different exposure specific water-regimes are formed through water run-off and run-on. As a consequence of limited infiltration the rainwater runs off the higher parts. The run on water keeps the deeper parts of the catena position longer wet

Subtypes of Meadow solonetz on the experimental field Mainly depending on the catena - moving from the highest position to the deeper one - the crusty (A = 0-7 cm), medium (A=8-20 cm) and deep (A > 20 cm) subtypes of the meadow solonetz soil can be found. On 25% of the soil cover in addition to the solonetzic character (ESPBhor > 5%). The solonchaky feature (water soluble salt content in the top layer > 0,15%) can be found as well. At the deepest catena position the soil is salt affected only in the deeper layers, so it belongs to the type of non salt affected meadow soil.

The chemical reclamation was made site specific On the soils with neutral or slightly acidic top layer lime was applied, while on the soils with alkaline top layer gypsum was used For regulation of drainage either surface or subsurface drainage was constructed. The surface drainage was made by outlet furrows. For internal drainage a tube system with an average depth of 1 m and 5, 10, 15 m drain spacing was constructed.

Exemplars of site specific reclamation TreatmentSoil subtypeTreatment code DIGO* (Spreading loess on the surface)400m 3 /ha crusty meadow solonetz(2) Gypsum in A horizoncrusty meadow solonetz(3,17) Gypsum in A and B horizoncrusty meadow solonetz(4,16) Lime in A horizon/gypsum in B horizon + 5 m drain crusty meadow solonetz(7,12) Lime in A horizon/gypsum in B horizon + 15 m drain crusty meadow solonetz(15) Lime in A horizon/gypsum in B horizon medium meadow solonetz(8) Lime in A horizondeep meadow solonetz(5) * Treatment “DIGO” is the oldest amelioration method of SAS in Hungary. Originally it was suggested by TESSEDIK 200 years ago. For improvement of SAS the CaCO 3 containing loess is mined and spread an amount of m 3 /ha (depending on the soil quality) on the surface of SAS.

The fertility* of a solonetz soil depends on the depth of leached A hor. *water and nutrient storage capacity rooting zone A-hor B-hor

Change of depth of A-horizon with low Na content (velocity of improvement) A-hor B-hor By means of drainage the average deepening of leached A- horizon was 20 cm/10 ys. Without drainage the thickness of the fertile topsoil with low salt content has deepened with approximately 10 cm/10 ys.

Winter wheat Y = 3,32+ 0,02*X -1,15E -4 *X 2 R 2 =0,4595 n=16 p=0,0183 Sunflower Y = 0,52+,028 *X -9,99E -2 *X 2 R 2 =0,7380 n=16 p=1,66E -4 Alfalfa hay Y = 1,41+ 0,03*X -1,04E -4 *X 2 R 2 =0,7888 n=16 p< Millet Y = 0,93+0,02 *X -9,29E -5 *X2R 2 =0,6669 n=16 p=7,88E -4 Gr.sorghum Y = 2,48 +0,07*X -4,92E -4 *X2 R 2 =0,1752 n=15 p=0,3149 Winter barley Y = 1,00+0,03*X +1,00E -6 * X2 R 2 =0,2982 n=16 p=0,1001 Relationship between depth A-horizon and the yield of different crops

Conclusion: Land use alternatives For arable land-use reclamation of sodic soils with deeper leached upper horizon and deeper ground water level must be preferred. If the leached A-horizon is shallower than cm and the ground water level frequently higher than 1.5 m the SAS can more economical be used as a pasture For meeting the demands of ecological and economical points of sustainability : velocity of improvement relationship between depth A-horizon and the yield of different crops

Land use possibilities third part in original state third part hay-field and grazing ground third part arable land (mainly winter wheat ) A=0-10cm A=10-20cm A>20cm

Thanks for your attention.